My b18a in my 90 civic hb gave up on me so I went and picked up another b18a, as I was switching the manifolds and all the other stuff over. I notice that on the new motor that I got doesn't have a sensor that the old one have I don't know what its called but it's number 31 on here http://acuraautomotiveparts.or...ormal
is this part needed for my car to work properly or is it a must have part.
Appreciate everyones help.

 

that is the oil temperature sensor and you don't need it

 

are you sure its the oil temperature sensor? last time i checked it said fan switch

 

29 would be the oil temperature sensor. no?

 

its the fan switch. the new motor should have it on the thermostat hosing instead of behind the block. just extend the wires to reach the new one and you will need the clip from any obd1 or 2 harness for the new switch

 

I am using the same thermo housing from my old motor since the new one didn't come with anything just the head and block. So since my old thermo housing don't have that sensor on it I guess the best thing to do is find a thermo housing that has one.

They are both b18a should they have all the sensor in the same place?

 

ok 29 is the oil pressuer switch and 31 is the oil temp switch

and yes they should all be in the same place unless you got a b18b block

i know the b18a1 block has it in the back by the oil filter under the water pipe

 

I checked the block again. they are both b18a1 blocks but the new block has a HM stamped under that serial number and the old one does not have the stamp on it. What is that supposed to stand for. Did it originally come with a auto trans? Anybody have a clue what the HM might stand for.

I took the sensor (number 31) off and radiator water came out of it so it might be the fan or some other water temp sensor.

 

HM stands for honda motors if for some reason your block does not have the thermo switch on the back just get a water outlet with the hole in it from any b18b if you are getting it from thew junk yard get the switch and plug/clip for it as well